Manufacture of dry-gummed flexible sheet material



- of adhesive, glue or gum, as

Y pleted product and Patented Mar. 3, 19 42 MANUFACTURE OF DRY-GUMMED' FLEXIBLE snEET MATERIAL Trevor R.

Nashua Nashua, N.

Gautier, Nashua, N. IL, assignor to Gummed and Coated Paper Company, IL, a corporation of Massachusetts Application November 25, 1938, Serial No. 242,171

'1 Claim.

My present invention relates to adhesive or gummed web material, of sheet and strip form, the latter commonly referred to as gummed tape, and more particularly to that of the dry gummed type as contrasted with the pressure or heat sensitive tapes and adhesive tapes of a normally sticky or non-dry character, such as surgical tape. The invention aims to provide a gummed sheet and strip material of the character referred to having improved adhering properties and other characteristics, including a reduced curling'tendency, at the same or less manufacturing cost, and at the same time to provide for readily identifying the particular product in a simple and permanent manner.

In the drawing illustrating by way of example one form of a sheet or strip resultant from the practice of the invention, and showing typical means for practicing the process or method of the invention,

Fig. 1 shows the gumined face of a relatively small area of the gummed sheet or strip;

Fig. 2 is an enlarged and somewhat diagrammatic sectional view of the material of Fig. 1;

Fig. 2a is a section, also partly diagrammatic, corresponding to a portion of Fig. 2, on a still larger scale;

Fig. 3 illustrates diagrammatically the several V steps of the manufacturing process; and

Figs. 4 and 5 are partially diagrammatic views of a gum marking or embossing means, in end and side elevation respectively.

Referring'first to Figs. 1 and 2 the material comprises a base 6 in flexible web form, generally of paper of the various types and weights commonly employed in the formation of gurnmed sheets and tape. Examples are manila and kraft papers of the various weights, but substantially any paper of suitabletensile strength may be employed. The invention is also applicable to dry gummed sheets and tapes flbrousbases, sometimes in combination with paper, including for example other fabric strips and tapes.-

At one face, or occasionally at both faces of the'base web 8, there is applied a layer or coating indicated at I in Figs. 1 and 2. This adhesive may be of any preferred composition, such for example as heretofore employed for the purpose. having a normal dry or substantially dry condition in the comhesive by the application of moisture. It is hereinafter referred to, for simplicity in description and without purpose of limitation, as gum.

having textile or other gummed linen and identification. Desirably the depressions are so adapted to be rendered adbase Web.

Distributed in the gummed area of the material, or that portion of said area which is to be adhesively employed, is a multiplicity of indentations or depressions 8, one process of forming .which will be further described in connection with Figs. 3 to 5. These indentations or depressed markings 8 are applied solely in and to the layer of gum 1, while the latter is in a fluid or semi-fluid condition, and in such fashion that they remain as low areas distinctly visible in the gum after the latter has dried.

As will be noted particularly in Figs. 2 and 2a, these formations 8 do not penetrate into the base web 6 of the paper or other material mentioned and hence do not weaken, deform or otherwise alter the structure of the base web. Preferably,

said depressions 8,at least in the completed products of my novel process, extend but partially through thethickness of'the gum layer 1, as seen in said Figs. 2 and 20, leaving the bottom surfaces of the depressions covered by a film of the gum material. This construction contrasts with that resulting from such treatment as scoring, scratching, cutting or other operation on the gum after it has dried on the web, and avoids any possibility of damaging the paper or other material of the base, the depressions being outside of the Referring to Fig. 1, said depressions 8 may be of various different conformationsas viewed in plan. Preferably they are of a shape, in plan, selected as distinctive and informative, as contrasted with mere lining or like ambiguous formation. Generally they include a multiplicity of individual or repetitive unit depressions composed of lettering or identifying markings such as a manufacturer's,

distributor's or company names, trade and brandv marks and the like, as represented by way of example by the script lettering m a rk in Fig. 1, any lettering being with or without other indicia. The unit depressions and any individual char"- acters in them may or may not be joined by one or more connecting lineal or other markings but desirably are arranged in a distinctive or arbi-.

trary recurrent manner, with non-depressed contiguous areas, so as to afford a readily intelligible arranged that an adequately identifying area thereof will be contained on the smallest portion of the gummed product likely to be handled separately, as a detached piece, in actual. use.

One important function and result of the provision of the described depressed formations I in the gum I is an improved adhering quality given the like arranged as distinctive to the g ummed face of the product. This apuct in subsequent parently is due in part to a capillary eflect set up at the shallow depressed areas and which tends to collect the moisture which is subsequently applied in rendering the gum adhesive for use.

which in turn applies it to the adjacent face of Resultantly some of the moisture, including possible excess moisture, is taken from the higher areas surrounding the depressed portions, causing it to accumulate at and in the latter, the depressions -8 acting as collecting reservoirs for the surrounding moisture. By thus withdrawing some portion of the moisture from the high or level areas, the latter are left covered more uniformly, with the desired thin film, approaching a true monomolecular film, of the moisture.

The capillary efifect at the walls of the well-like depressions 8 and the surface tension over the collecting moisture supplies in the depressions tends to retain these in a position, frequently with a convex meniscus, as represented diagrammatically at m in the greatly enlarged sectional view of ,Fig. 2a. These supplies accordingly are automatically held available for redistribution, in application of the moistened gummed material to a surface, to any insufliciently moistened areas as the gum is dissolved or renderedadhesive in readiness for such application. This collective or draining andstoring eifect is somewhat more pronounced where the depressed areas 8 are more or less interrupted or non-rectilinear, as contrasted with extensive uniform lining or channeling.

The improved adhering quality of the material is also due in part to the substantially increased surface area of gum which is exposed to receive moisture, in any given area of the base web 6. As will in connection with Fig. 2a. the exposed gum surface is increased' by approximately the total area of the lateral walls of the depressions, less any difference in area between the bottom walls of the depressions and the area of their open mouths resulting from an walls. The moisture is thus enabled to attack the gum laterally, as indicated by the small arrows in Fig. 2a, and over thematerially increased surface area provided by the depression side walls, as contrasted with access only to the plane surface of the gum and in a direction normal to it. Said depressions-also tend to reduce or retard curling of the resulting dry gummed produse, due apparently to the interruption, particularly by any curvilinear and angular depressed areas, of the otherwise substantially uniform gummed surface and to the reduced thickness of the gum at the base of the depressed areas, A still further advantage lies in the fact that less gum need be employed, with an attendant cost saving, since a thinner gum layer as a. whole may be used in view of the improved adherence obtained with the depressively marked product.

In accordance with the novel process or meths d of the invention as illustrated in connection with Figs. 3 to 5, the depressions 8 are formed in the'gum coating or layer 7 attendant on the application of the latter to the base web 8., The ungummed paper or web 6 is conducted at a predetermined rate of travel, as by being drawn by a re -winder later referred to, from a rotatably supported supply roll to the gum applying mechanism, illustrated in Fig. 3 as including a fluid gum container H receiving a transfer roll l2. The latter transfers the liquid adhesive or gum from the container to an applicator roll I3 the web 6, in t instance the under face. The web, now having the layer of gum 1 at its under face, continues its travel across a smoothing bar or roll I 4, seen also in Figs. 4 and 5. As there shown the smoothing bar It is rotatably sup-. ported removably in bearings l5 mounted on the frame l6 of the gumming machine, as by a bracket l1. It is preferably driven by suitable gearing (not shown) in a direction reverselyto that of the travel of the web.

Forwardly beyond the smoothing bar H but sufficiently close to it so that the gum does not have opportunity to dry or harden beyond a semi-fluid condition, I provide a gum marking or embossing roll 20, rotatably mounted for ready removal in bearings 2| supported on the gummer frame It, as by said bracket [1. The surface of the roll 20 has formed on or applied to it the raised formations 22, seen in Fig. 5, of the shape, area and arrangement as desired for the depressions 8 to be formed in the gum layer 1.

The marking roll 20 is so disposed with respect to the smoothing bar l4 and to the next following contacting support for the web that the latter is turned somewhat around the roll, changing be apparent particularly inclination of the side the plane of its path through a relatively flat I angle, such for example as represented in Figs. 3 and 4. This angle is made suflicient to insure a pressingcontact of the gum layer 1 upon the raised portions 22 of the roll 20, over but a small segment of the latter, as the web crosses said roll. Thus the advancing web is tensioned and biased toward said raised portions or embossing formations 22. I The marking element or roll 20 is arranged to have the same or substantially the same surface speed as for th web itself, the roll receiving its rotary movement from the web or being driven in accurately timed relation with the web-moving mechanism of the gummingmachine.

-In order to avoid adherence of the gum to the marking roll or drum 2!] and distortion of the outlines for the depressions in the gum, I desirably provide means for maintaining the surface of the marking roll 20 and the marking formations 22 thereon in a constant wetted condition. For this purpose I have herein illustrated in Figs. 4 and 5 a moistener device comprising a tube or pipe 24 adjacent and paralleling the marking roll 2!], herein below it. This moistener tube 24 is supplied with moisture, such as a low pressure wet steam or in some cases water from any suitable source, as by means ofthe supply pipe 25. The tube 24 is apertured along its portion opposite the marking'roll 20 to apply the steam, vapor or other moisture 26 to the marker roll 20, in a multiplicity of jets or spraysas indicated in the figures or otherwise so as to maintain an evenly distributed filmof moisture upon the surface and the marking formations 22 of the marker roll 20. Any tendency of the gum to come off onto the marking roll is thus substantially overcome. this point tends also to resoften any portions of the gum which may have hardened unduly rapidly.

Beyond the described g'um marking orembossing means the paper or other gummed sheet or strip material, nowhaving. the depressions 8 .formed in its gum layer 1, is dried, as by conducting it to or past suitable drying means not necessary to illustrate herein and thence to a re-winder. The web 6 as supplied from the roll l0 may be The moistening action at of any desired width, generally one or more feet. In connection withthe rcwinding, or subsequently, the web may be slitted longitudinally to provide sheets, strips or tapes of any desired widths, as customary for example in the manufacture of gummed paper strip and tape products.

From the foregoing it will be understood that V certainty, no satisfactory and inexpensive mark ing for this purpose having heretofore been devised.

My invention is embodiment nor to method thereof as herein illustrated and described, its scope being pointed out in my following claim.

I claim:

In the manufacture of dry-gum-coated paper not limited to the particular and like flexible web and strip material subsequently to be rendered adhesive for use, the process which comprises conducting from a sup-' ply a base web of such material, applying gum coating to at least one face of the web, further advancing the coated web prior to dry-hardening of its gum coating, providing gum-embossing formations of selected area and contour and moving them adjacently to a coated face of the web in the direction of the web advance and at substantially the same linear speed, establishing and maintaining a wetted condition for the embossing formations to avoid adherence of gum thereto, tensioning the advancing web in a manner biasing its adjacent coated face toward the embossing formations and thereby effecting pressing contact of the latter'with the gum coating while the means for practicing the it is in semi-fluid condition so as to form corresponding embossed areas solely in and but partially through the coating. and continuing the advancing travel of the web and drying its gum coating while prominently retaining said embossed areas in it for adhesive efliciency improving and marking purposes. a

TREVOR R. GAUTIER. 

